Chain-driven incline

ABSTRACT

In a unit carrier system in which a plurality of cars are driven over a trackway by means of the frictional interaction of reaction surfaces and propulsion wheels, apparatus for transmitting relatively large amounts of power to the cars. The apparatus comprises a plurality of brackets carried on endless chains in the trackway and the inner surface of which are shaped to conform to the shape of the outer surface of the reaction members mounted on the car. The reaction member mounted on the car nests itself in one or more of the brackets, and the car is pulled along by a motor which drives the chains.

United States Patent 1191 Peppard Nov. 5, 1974 CHAIN-DRIVEN INCLINE 3,114,332 12/1963 B86011 Et al 104/168 lnvgmorz William D- pp Chico, Calif 3,626,859 l2/l97l Bradbury l04/l68 [73] Assignee: Rexnord Inc, Milwaukee, Wis. Primary Examiner-M. Henson Wood, Jr. Assistant Examiner-Robert Saifer [22] Filed 1973 Attorney, Agent, or FirmSughrue, Rothwell, Mion, [21] Appl. No.: 336,592 Zinn & Macpeak Related US. Application Data ABSTRACT [63] Continuation-impart ofSer, No. 318,980, Dec. 27,

1972 abandone In a un1t carr1er system 1n wh1ch a plura11ty of cars are driven over a trackway by means of the frictional in- 52] us. c1. 104/165 104/166 tcractiO" of reaction Surfaces PmPulSiO Wheels 51 1m. (:1 B616 13/12 apparatus for transmitting relatively large amounts of [58] Field of Search 104/165, 166, I68, 172 R, POWer the The aPPardtus S R a plurality 104/172 B 172 S 178 168 of brackets carried on endless chams 1n the trackway and the inner surface of which are shaped to conform [56] References Cited to the shape of the outer surface of the reaction mem bers mounted on the car. The reaction member UNITED STA TES PATENTS mounted on the car nests itself in one or more of the 7 Qcklm gy/ brackets, and the car is pulled along by a motor which 0S6 t v 3,013,499 12/1961 Hubert 104/165 dr'ves the sham 3,058,433 l0/l962 Hurst 104/172 8 9 Claims, 9 Drawing Figures PATENTEU 5 1974 3,845,722 SHEEI 10F 3 CHAIN-DRIVEN INCLINE CROSS REFERENCE TO A RELATED APPLICATION FIELD OF THE INVENTION This invention relates generally to apparatus for transmitting power to the cars of a unit carrier'system in which a plurality of cars are driven over a trackway, and, more specifically, to apparatus for changing the elevation of cars in a unit carrier system such as is disclosed in commonly assigned US. Pat. Nos. 3,621,790, 3,626,859 and 3,650,216.

BACKGROUND OF THE INVENTION In a unit carrier system it is often desirable to change the elevation of the track because the system extends through a part of a building or complex of buildings on different levels of terrain or because the system extends to different floors of the same building. Such a change of elevation can be accomplished by simply including an incline section of track in the system. However, in friction-powered unit carrier systems such as the one disclosed in the above-listed patents, the amount of normal force between the reaction tubes and the propulsion wheels is limited to something less than the weight of the cars in order to provide stable operation. This limitation in turn limits the power transmission capabilities of this drive technique to values less than that desirable at certain critical points in the sytem e.g., where the cars have to climb steep inclines and where they must be accelerated from zero velocity in a queing station to the velocity of the cars on the main line. The present invention is designed to supplant the frictionpowered drive apparatus at such critical points in the system, allowing the cars to be driven up a steeper incline or accelerated on to the main line more rapidly than they otherwise could be.

SUMMARY OF THE INVENTION BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of a chain-driven incline incorporating the present invention.

FIG. 2 is a side elevational view taken along the line lI--II in FIG. I.

FIG. 3 is an enlarged view of the portion of FIG. 2 included within the circle III.

FIG. 4 is a plan view of a portion of the chain-driven incline shown in FIG. I. v

FIG. 5 is a view taken along the line V-V in FIG. 4.

'FIG. 6 is a view taken along the line VIVI i FIG. 5.

FIG. 7 is an enlarged view of the portion of FIG. 4 included within the circle VII.

FIG. 8 is a front view of an alternative embodiment of the brackets used in the present invention.

FIG. 9 is a side view of the embodiment shown in FIG. 8.

DETAILED DESCRIPTION OF TWO PREFERRED EMBODIMENTS While the present invention could be used at a queing station such as is described in commonly assigned US. Pat. Nos. 3,626,859 or at a merge such as is described in commonly assigned US. application Ser. No. 315,059, filed Dec. 24, 1972, it finds its most ready application at trackway inclines because of the necessity of wedging the cylindrical reaction member into the brackets. This wedging operation can be accomplished most conveniently when the cylindrical reaction member and the brackets are all moving at the same speed, though it can be accomplished in connection with a stop. Accordingly, the preferred embodiment described herein utilizes the present invention at a trackway incline.

FIG. 1 is a plan view of an incline in the trackway. As indicated by the arrow, traffic moves from left to right, ascending the incline, which comprises tracks 10 mounted on crossties l2 and a chain-driven apparatus 14 incorporating the present invention. This apparatus com asses-mater 16 mounted onbn'efift hetraiiksif) at the upper end thereof and operatively connected to a sprocket 18 mounted on a shaft 20. The shaft 20 turns freely in bearings 22 mounted on the tracks 10, and centrally mounted thereon are sprockets 24. At the lower end of the tracks 10, sprockets 26 are similarly centrally mounted for free rotation, and connecting sprockets 24-to sprockets 26 are chains 28, which are guided between sprockets by chain guides 30, best seen in FIGS. 3and 5. i

Carried between the chains 28 are a series of saddleshaped brackets 32, best seen in FIGS. 4, 5, 6, and 7. As shown by FIG. 4, the brackets 32 are carried at evenly spaced intervals and are perpendicular to the direction of the chains. If the brackets are mounted at close intervals relative to the length of the portion of the car which they engage, no special timing mechanism is required, the cars simply engaging whichever brackets are at hand when they come to the bottom of the apparatus. Y

Each bracket 32 comprises an elastomeric pad 34 and a metal plate 36 mounted on a bar 38. The pads 34 and the plates 36 are both shaped to receive a reaction member 40 mounted on the bottom of a car (not shown) of the unit carrier system. In principle, the reaction member 40 could be either a powered, propulsion member or a freely rotating reaction member. However, since in the former case the power would ordinarily have to be turned off before the propulsion member came into contact with the bracket, it seems likely that the present invention will more often be used in the latter situation. The elastomeric pads 34 are provided to cushion the impact between the reaction member 40 and the saddle-shaped bracket 32 and to facilitate a wedging of the reaction member 40 into the saddle of they saddle-shaped brackets 32, thereby increasing the effective coefficient of friction between the brackets 32 and the reaction member 40.'Alternatively or additionally, the reaction member 40 may be made of, or coated with, a resilient material, thereby accomplishing the same purpose.

The brackets 32 further comprise attachment links 42 which connect the brackets 32 to the chains 28. As mentioned previously, the chains 28 are guided by chain guides 30, which comprise extruded wear strips 44 and angle irons 46 mounted on a backing plate 48. The backing plate 48 is in turn mounted on the crossties 12.

In operation, the incoming and outgoing track speeds should be essentially equal to the linear speed of the chains 28 so that no abrupt changes in velocity are imparted to the car. Rather, the forward motion of the car should gently but firmly wedge the reaction member 40 into the saddle of one or more of the saddle-shaped brackets 32. An entry radius and an exit radius at the bottom and top of the incline, respectively, are provided to allow for a transition from and to the power transmission system powering the car elsewhere in the system while the car is moving horizontally. A flaring of the beginning of the chain guides 30 is clearly shown in FIG. 3. I

An alternative embodiment of the brackets used in the present invention is depicted in FIGS. 8 and 9. In this embodiment, the bracket 32 is U-shaped in longitudinal cross section, rather than rectangular, and two separate elastomeric wear pads 50 are mounted on each leg of the bracket, rather than the single, saddleshaped wear pad 34 previously disclosed. These are independent variations on the original theme, either being usable without the other. The purpose of using a U-shaped bracket rather than a rectangular bracket is to distribute the torque caused by the engagement of the reaction member 40 with the wear pads over a longer portion of the chain 28. However, the amount by which the length of the bottom portion of the U- shaped bracket exceeds the length of each chain link somewhat raises the minimum size of the sprockets about which the bracket-bearing chain can be turned. Similarly, the purpose of ,using separate elastomeric wear pads such as are shown in FIGS. 8 and 9 rather than a single, saddle-shaped wear pad such as is shown in FIG. is to facilitate fabrication and replacement of the wear pads, but advantages along those lines are gained at the expense of a loss in the strength of the gripping action. Which of the possible combinations of these themes and variations will be used in a specific situation will depend, of course, on the specific requirements which must be met.

CAVEAT While the present invention has been illustrated by a detailed description of a preferred embodiment thereof, it will be obvious to those-skilled in the art that various changes in form and detail can be made therein without departing from the true scope of the invention. For that reason, the invention must be measured by the claims appended hereto and not by the foregoing preferred embodiment.

What is claimed is:

1. In a friction-powered unit carrier system having a plurality of cars which are normally driven over a trackway by the interaction of cylindrical, longitudinally extending reaction members mounted on said cars and powered propulsion wheels mounted adjacent to said trackway, a device for transmitting relatively large amounts of power to said cars comprising:

A bracket having a saddle therein adapted to releasably engage said reaction members, said bracket being U-shaped means for moving said bracket along said trackway, whereby a car on which is mounted a reaction member releasably engaged by said bracket may be pulled forward by said bracket.

2. A device as claimed in claim 1 wherein said means for moving said bracket along said trackway comprise:

two endless chains which carry said bracket thcrebctween,

chain guidesv which guide said chains along said trackway, and

a motor which drives said chains.

3. A device as claimed in claim 1 where said device is adapted to change the elevation of said cars.

4. A device as claimed in claim 3 wherein said means for moving said bracket along said trackway comprises:

two endless chains which carry said bracket therebetween,

chain guides which guide said chains along said trackway, and

a motor which drives said chains.

5. A device as claimed in claim 4 wherein said chain guides have an entry radius which allows a transition to said device from the power transmission system powering said car prior to said device while said cars are moving horizontally.

6. A device as claimed in claim 4 wherein said chain guides have an exit radius which allows a transition from said device to the power transmission system powering said cars after said device while said cars are moving horizontally.

7. A device as claimed in claim 1 wherein said bracket comprises;

a plate having aninner surface shaped to conform to the shape of the outer surfaces of said reaction members, which inner surface constitutes the previously recited saddle, and

an elastomeric pad mounted on the inner surface of said plate, which pad is adapted to cushion the impact between said cars and said bracket and to facilitate a wedging of said reaction members into the inner surface of said plate, thereby increasing the effective coefficient of friction between said bracket and said reaction members.

8. A friction-powered unit carrier system as claimed in claim 1 wherein said cylindrical, longitudinally extending reaction members are made of a resilient material, which material is adapted to cushion the impact between said cars and bracket and to facilitate a wedging of said reaction members into the saddle of said bracket, thereby increasing the effective coefficient of friction between said bracket and said reaction members.

9. A device as claimed in claim 1 wherein said bracket comprises:

a plate having an inner surface shaped to conform to the shape of the outer surfaces of said reaction members, which inner surface constitutes the previously recited saddle, and

a plurality of elastomeric pads mounted on the inner surface of said plate and adapted to cushion the impact between said cars and said bracket and to facilitate a wedging of said reaction members into the inner surface of said plate, thereby increasing the effective coefficient of friction between said bracket and said reaction members. 

1. In a friction-powered unit carrier system having a plurality of cars which are normally driven over a trackway by the interaction of cylindrical, longitudinally extending reaction members mounted on said cars and powered propulsion wheels mounted adjacent to said trackway, a device for transmitting relatively large amounts of power to said cars comprising: A bracket having a saddle therein adapted to releasably engage said ereaction members, said bracket being U-shaped means for moving said bracket along said trackway, whereby a car on which is mounted a reaction member releasably engaged by said bracket may be pulled forward by said bracket.
 2. A device as claimed in claim 1 wherein said means for moving said bracket along said trackway comprise: two endless chains which carry said bracket therebetween, chain guides which guide said chains along said trackway, and a motor which drives said chains.
 3. A device as claimed in claim 1 where said device is adapted to change the elevation of said cars.
 4. A device as claimed in claim 3 wherein said means for moving said bracket along said trackway comprises: two endless chains which carry said bracket therebetween, chain guides which guide said chains along said trackway, and a motor which drives said chains.
 5. A device as claimed in claim 4 wherein said chain guides have an entry radius which allows a transition to said device from the power transmission system powering said car prior to said device while said cars are moving horizontally.
 6. A device as claimed in claim 4 wherein said chain guides have an exit radius which allows a transition from said device to the power transmission system powering said cars after said device while said cars are moving horizontally.
 7. A device as claimed in claim 1 wherein said bracket comprises; a plate having an inner surface shaped to conform to the shape of the outer surfaces of said reaction members, which inner surface constitutes the previously recited saddle, and an elastomeric pad mounted on the inner surface of said plate, which pad is adapted to cushion the impact between said cars and said bracket and to facilitate a wedging of said reaction members into the inner surface of said plate, thereby increasing the effective coefficient of friction between said bracket and said reaction members.
 8. A friction-powered unit carrier system as claimed in claim 1 wherein said cylindrical, longitudinally extending reaction members are made of a resilient material, which material is adapted to cushion the impact between said cars and bracket and to facilitate a wedging of said reaction members into the saddle of said bracket, thereby increasing the effective coefficient of friction between said bracket and said reaction members.
 9. A device as claimed in claim 1 wherein said bracket comprises: a plate having an inner surface shaped to conform to the shape of the outer surfaces of said reaction members, which inner surface constitutes the previously recited saddle, and a plurality of elastomeric pads mounted on the inner surface of said plate and adapted to cushion the impact between said cars and said bracket and to facilitate a wedging of said reaction members into the inner surface of said plate, thereby increasing the effective coefficient of friction between said bracket and said reaction members. 